10.2 - Marine, Beach, and Coast.pdf

-f---------------------------------- MARINE ENVIRONMENT, BEACH AND COASTAL ENVIRONMENT KIN DELOS REYES AND NIKKA VILLANUEVA FIRST SEMESTER|CORRELATION 1 MINING, CERAMICS AND GEOLOGY DEPARTMENT MARINE REALM MORPHOLOGY AND PROCESSES INTRODUCTION Oceans and seas of the world cover almost three-q...

-f---------------------------------- MARINE ENVIRONMENT, BEACH AND COASTAL ENVIRONMENT KIN DELOS REYES AND NIKKA VILLANUEVA FIRST SEMESTER|CORRELATION 1 MINING, CERAMICS AND GEOLOGY DEPARTMENT MARINE REALM MORPHOLOGY AND PROCESSES INTRODUCTION Oceans and seas of the world cover almost three-quarters of the surface of the planet There is variety in the sedimentation but there are processes that are common to many of the marine environment. o Physical Processes o Chemical Processes o Biochemical Processes MARINE REALM Very large regions of coastal, benthic or pelagic ocean across which biotas are internally coherent at higher taxonomic levels, as a result of a shared and unique evolutionary history. DIVISION OF THE MARINE REALM (1 ) BAT HYME T RY • • • • • T h e sh ap e an d d e p t h o f t h e se a f lo o r Origin ally refe rs to t h e o ce an ’s d ep th re lat ive to se a leve l “ Su b marin e To p o grap hy ” D ete rmin e th e p late te cton ic p ro ce sse s Bat hymet ric m a p co n n e ct po int of e q u al d e p t h PROFILE B AT H Y M E T R I C P R O F I L E 2kmL 100km • Most of the ocean floor is between about 4000 and 5000 m below sea level. • The deepest parts of the oceans are the ocean trenches (10,000 m depth). • At the ocean margins the transition from ocean crust to continental crust underlies the continental slope (steeper angle 2 and 7 degrees) • Continental rise (gentle angle) down to the edge of the abyssal plain (flat depositional surface on the seafloor). • While the continental shelf (20m BSL) is the shallow submarine terrace of continental crust. continental shelf land continental slope continental rise X X X X X X X X X X X X X X X X X X X X X X X X x::::,Continental crust t:::::x abyssa l plain xxxxxxxxxxxxxxxxxxxxxxxxxxxxx Sea Surface Shelf Volcanic Island Co ntinental Slope Continental Rise 4 , 000 to 6,000 m Submarine Ridge Oceanic Trench 10,000m - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - SHELF SHELF (further division) •• N E R I T IIC C ZZONE ONE| Shelf area NERI to 200 meter water depth •• BBATHYAL AT H YA L ZZONE ONE| Continental slope and extends from 200 meters to 2000 meters water depth •• A BY S S A L ZZONE ONE| Ocean floor ABYSSAL below 2000 meters •• H A D A L ZZO O N EE| G r e a t e r t h a n HADAL 5000 m e t e rs depth, deepest parts of the oceans shelf edge break sea level 200m -sea level mean high water mean low water foreshore I fair weather wave base shoreface I storm wave base offshore-transition I offshore NETRIC ENVIRONMENT NETRIC E NV IRO N ME N T (further division) •• FORESHORE| FORESHORE The region between mean high water and mean low water marks of the tides and is part of the littoral zone •• SHOREFACE| SHOREFACE The region of the shelf between the low-tide mark and the depth to which waves normally affect the sea bottom, and this is the fair weather wave base. •• OFFSHORE-TRANSITION ZONE| The ZONE deeper shelf area between the fair weather and storm wave bases. •• OFFSHORE ZONE| ZONE The region below storm wave base and extends out to the shelf edge break at around 200 meters depth. .sea level sto:rm wave base - TIDES TYPES OF TIDES T I D ES ( 1 ) S P R I N G T I D ES The cyclic rising and falling of Earth’s ocean surface caused by the tidal forces of the Moon and the Sun acting on the Earth. TIDAL BULGE| BULGE Bulge of water due to strong gravitational attraction between water and moon DIURNAL DIURNAL TIDES| TIDES At any point on the surface the level of the water will rise and fall twice a day as the two bulges are passed in each rotation Earth DIURNAL DIURNAL TIDAL centre of mass INEQUALITY| of Earth-Moon INEQUALITY system Moon Also called a mixed Sun tide or the difference 0 in height between successive high tidal bulge Earth's orbit of in oceans Moon completes orbit (or low) tides. of Earth in 1month. Sun is elliptical. V Earth rotates under each tidal bulge once each day - results in two tides each day When aligned with Sun (twice amonth), spring tides occur. When perpendicular, neap tides occur When the Earth is closest (spring and autumn equinoxes), tides are highest  When the sun and moon are aligned, there are exceptionally strong gravitational forces, causing very low tides  Occur during the full moon and the new moon. ( 2 ) N EA P T I D ES  When the sun and moon are p e r p e n d i c u l a r, t h e g rav i tat i o n a l fo rc e s ca n c e l e a c h o t h e r o u t , a n d t h e t i d e s a re n o t a s d ra m at i ca l l y h i g h a n d l o w, t h e s e o c c u r d u r i n g q u a r te r m o o n s . 0 Tide Type 3rd Qtr, •@;@◄ Tide Type llitdM () .,, I I .,, ,, .,. 0 ... ,, 0 '\ \ \ I I • 0 New Moon , \ Earth \ ,,." ' I I I ' ... , ... ___ ,,,."" .,, I () • • I \ I \ \ I TIDES CHARAC TERISTICS OF TIDAL CURRENTS ff'ow offshore ,as tide falls 7-----..-.......--..-........-..---l ebb tide rn rriem 1 I FIRST| Bipolar currents acting in two FIRST opposite directions <flow onshore ,as tide rises· flood 1ide curfie nt ,b w tide levm Higih t.ide SECOND| SECOND The tidal flow varies in velocity in a cyclical manner. THIRD| THIRD The strength of the flow is directly related to the difference between the level of high and low tides. maximum flow . .slacik water - ----3;.-- Low·tide I._______J_ _ ____l_ _ __l__J Twic-e daily tidal cycle Time TIDAL CURRENTS The vertical motion of the tides near the shore causes the water to move horizontally, creating tidal currents. When a tidal current moves toward the land and away from the sea, it “floods.” When it moves toward the sea away from the land, it “ebbs.” Herringbone cross-stratification Features that indicate tidal influence of transport and deposition: (a) Herringbone cross-stratification; Mud drapes on cross-beds (b) Mud drapes on cross-bedding formed during the slack water stages of tidal cycles; (c) Reactivation surfaces formed by erosion of part of a bedform when a current is reversed. Reactivation surface (erosion surface within a set of cross-beds) WAVES AND STORM PROCESSES WAV E S A N D S TO R M P R O C E S S E S The depth to which surface waves affect a water body is referred to as the wave base and on continental shelves two levels can be distinguished: i. ii. The fair weather wave base is the depth to which there is wave-influenced motion under normal weather conditions. The storm wave base is the depth waves reach when the surface waves have a higher energy due to stronger winds driving them. Storms are weather systems that have associated strong surface winds, typically in excess of 100 km/h, and they may affect both land and marine environments. Tsunami It has been suggested that beds of poorly sorted debris containing a mixture of deposits and fauna may form as a consequence of tsunami. THERMO-HALINE AND GEOSTROPHIC CURRENT THERMO-HALINE CURRENT - Deep-ocean currents are driven by differences in the water’s density, which is controlled by temperature (thermo) and salinity (haline) (thermohaline circulation) - Weaker than storm and tidal current but larger in volume GEOSTROPHIC CURRENT - Wind driven currents related to the global wind systems, which result from differences in air mass temperatures combined with the Coriolis force lln ty PSS) 32 38 CHEMICAL AND BIOCHEMICAL SEDIMENTATION BLACK SHALE  A mudrock that typically contains 1–15% organic carbon  Organic-rich sediments  Black or dark grey color is partly due to the presence of the organic matter GLAUCONITE  Dark green mineral that is found quite commonly in marine sediments.  Material made up of any of these distinctive, medium to dark green minerals is referred to as glaucony. PHOSPHORITES  sedimentary rocks that are enriched in phosphorus to a level where the bulk composition is over 15% P2O5  Material made up of any of these distinctive, medium to dark green minerals is referred to as glaucony. SHALLOW SANDY SEAS INTRODUCTION TERRIGENOUS CLASTIC MATERIAL SHALLOW MARINE ENVIRONMENTS Are areas of accumulation of substantial amounts of terrigenous clastic material brought in by rivers from the continental realm. Estebl ed b normarol ( i 2500 ml$0bath 100 t) 350 cootl n cru 1 l'lcnl 1 Is distributed on shelves and epicontinental seas by tides, waves, storms and ocean currents: these processes sort the material by grain size and deposit areas of sand and mud, which form thick, extensive sandstone and mudstone bodies in the stratigraphic record. SHALLOW SEAS SEDIMENT SUPPLY TO SHALLOW SEAS  The supply of sediment to shelves is a fundamental control on shallow marine environments and depositional facies of shelves and epicontinental seas.  Shallow seas that are not supplied by much terrigenous material may be areas of carbonate sedimentation, especially if they are in lower latitudes where the climate is relatively warm. SHALLOW MARINE CLASTIC ENVIRONMENT  The patterns and characteristics of deposition on shelves and epicontinental seas with abundant terrigenous clastic supply are controlled by the relative importance of wave, storm and tidal processes.  Open shelf areas facing oceans are typically regions with a microtidal to mesotidal regime and are affected by ocean storms. Two main types: 1. Storm-dominated shelves 2. Tide-dominated shelves **Can be recognize in both modern environment and ancient facies.** SHALLOW SEAS • HUMMOCKY CROSS-STRATIFICATION Is distinctive in form, consisting of rounded mounds of sand on the sea floor a few centimetres high and tens of centimetres across. • SWALEY CROSS-STRATIFICATION Between the hummocks lie swales and where concave layers in them are preserved. CRITERIA FOR THE RECOGNITION OF SANDY SHALLOW-MARINE SEDIMENTS 1) The physical processes are generally distinctive 2) The organisms that occur in shelf deposits are distinctive of shallow marine conditions, either as body fossils. 3) Successions of shelf sandstones and mudstones may also be associated with limestones deposited during periods of low supply of terrigenous clastic detritus. SHALLOW MARINE CARBONATE AND EVAPORITE ENVIRONMENTS CARBONATE DEPOSITIONAL ENVIRONMENTS Features of shallow marine carbonate environments: • They are largely composed of sedimentary material that has formed in situ (in place), mainly by biological processes. • The grain size of the material deposited is largely determined by the biological processes that generate the material. • The biological processes can determine the characteristics of the environment • The production of carbonate material by organisms is rapid in geological terms, and occurs at rates that can commonly keep pace with changes in water depth due to tectonic subsidence or eustatic sea-level rises: Controls on carbonate sedimentation • Isolation from clastic supply The primary requirement for the formation of carbonate platforms is an environment where the supply of terrigenous clastic and volcaniclastic detritus is very low and where there is a supply of calcium carbonate. • Shallow marine waters Relatively shallow waters with low amounts of suspended terrigenous clastic material are therefore most favourable. sea level carbonate productivity light saturation zone ___________ 10- 20m -------------- This shallow region of high biogenic productivity is referred to as the carbonate factory. base of photic zone -1 oom Morphologies of shallow marine carbonateforming environments Carbonate Platform - can be generally applied to any shallow marine environment where there is an accumulation of carbonate sediment. - Areas of shallow marine carbonate sedimentation that can occur in a variety of climatic and tectonic settings. Morphologies of shallow marine carbonate-forming environments Epeiric platform, • Carbonate Shelf if the platform is attached to a continental mass • Carbonate banks are isolated platforms that are completely surrounded by deep water • Carbonate atoll formed above a subsiding volcano island • Carbonate ramp with gentle slope (<1⁰) down deep water with no break in slope • Flat-topped with a sharp change in slope at the edge forming a steep margin, either as rimmed or nonrimmed shelf !so.lated platfonn, ------------ ;;;3 : : : : : : : : : ;: ji ,< 1 - 100km Ramp [ j j j I I I I i 10-100km Non-rimm.e d shelf Rimm.e d shelf ~~ [ I ii Ii ii ii 10-1QQkm :??§<s =_J il i lil il i lil ~ ~ - - - - - - - - - - - - - - - - - - -- -- COASTAL CARBONATE AND EVAPORITE ENVIRONMENTS • Beach - Where wave energy is strong, sandy and gravelly material may be reworked on the foreshore forming low-angle stratification of well sorted and wellrounded sediments. - Carbonate material in the form of bioclastic debris and ooids is reworked by wave action into ridges that form strand plains along the coast or barrier islands separated from the shore by a lagoon. Beaoh dune ridge Beaoh iCoas,fal plain Foreshore Benn Baokshore • ·: ; ~ • ' . . . • • • • • . ■ •,, . : . : ·, : ·· ... . ~- • Barrier and Lagoon System -Barrier of sediments separates the open sea from a lagoon that lies between the barrier and the coastal plain. -Lagoons are coastal bodies of water that have very limited connection to the open ocean only through a channel to the sea or via seepage through a barrier. Lagoons form along carbonate coastlines where a beach barrier wholly or partly encloses an area of shallow water. The character of the lagoon deposits depends on the salinity of the water and this in turn is determined by two factors: the degree of connection with the open ocean and the aridity of the climate. • Carbonate Lagoons - are sites of fine-grained sedimentation forming layers of carbonate mudstone and wackestone with some grainstone and packstone beds deposited as washovers near the beach barrier. • Arid Lagoons -In hot, dry climates the loss of water by evaporation from the surface of a lagoon is high. If it is not balanced by influx of fresh water from the land or exchange of water with the ocean the salinity of the lagoon will rise and it will become hypersaline, more concentrated in salts than normal seawater. An area of hypersaline shallow water that precipitates evaporite minerals is known as a saltern. Deposits are typically layered gypsum and/ or halite occurring in units meters to tens of meters thick. c stone/ ,a· ~~-:~~~::l~";·-.. i,.,J....~;;' ~ ' • Supratidal carbonate flats The supratidal zone lies above the mean high water mark and is only inundated by seawater under exceptional circumstances, such as very high tides and storm conditions. Where the gradient to the shoreline is very low the supratidal zone is a marshy area where microbial (algal and bacterial) mats form. • Arid Sabkha Flats Arid shorelines are found today in places such as the Arabian Gulf, where they are sites of evaporite formation within the coastal sediments. These arid coasts are called sabkhas. Gypsum and anhydrite grow within the sediment while a crust of halite forms at the surface. coastal sabkha evaporite crusts evaporite crusts extensive microbial mats high salinrty shallow marine high salinrty shallow marine • Intertidal carbonate deposits In the intertidal zones deposits of lime mud and shelly mud are subject to subaerial desiccation at low tide. supratklal marsh (carbonate pavement) intertidal carbonate mud flats with m\crob\a\ mats SHALLOW MARINE CARBONATE ENVIRONMENTS • The character of deposits in shallow marine carbonate environments is determined by the types of organisms present and the energy from waves and tidal currents. • The sources of the carbonate material are predominantly biogenic, including mud from algae and bacteria, sand-sized bioclasts, ooids and peloids and gravelly debris that is skeletal or formed from intraclasts. Bioturbation is usually very common and faecal pellets contribute to the sediment. • Carbonate sand shoals • Reefs Sediment composed of sand to Reefs are carbonate bodies built granule-sized, loose carbonate up mainly by framework- building material occurs in shallow, high energy benthic organisms such as corals. areas. They are wave-resistant structures These carbonate shoals may be made that form in shallow waters on up of ooids, mixtures of broken shelly carbonate platforms. debris or may be accumulations of benthic foraminifers. Reef build-ups are sometimes referred to as bioherms: carbonate Reworking by wave and tidal currents build-ups that do not form domeresults in deposits made up of wellshaped reefs but are instead sorted, well-rounded material: when tabular forms known as lithified these form beds of grainstone, biostromes. or sometimes packstone. Reef Environment • • • • • • Back Reef Reef Flat Reef Crest Reef Front Reef Front lower Fore-Reef Front Zone • Barrier Reef • Carbonate Mud Mounts - A carbonate mud mound is a sediment body consisting of structureless or crudely bedded fine crystalline carbonate. Modern examples of carbonate mud mounds are rare. Many mounds are made of the remains of microbes that had calcareous structures and these microbes grew in place to build up the body of sediment. • Outer shelf and ramp carbonates - On the outer parts of shelves carbonate sedimentation is dominated by fine-grained deposits. - These carbonate mudstones are composed of the calcareous remains of planktonic algae and other fine grained biogenic carbonate. - This facies is found in both modern and ancient outer platform settings and when lithified the fine-grained carbonate sediment is called chalk. Swamps, marshes, and bogs They are all examples of wetland which is a transitional between permanently aquatic and terrestrial environment. In wetlands, the watertable sits at or close to the surface of the land, and shallow water often covers the area. The types of wetland only differ with the plant species found there.  Swamp- tall trees (woody vegetation)  Marshes- grasses  Bogs- mosses DEEP MARINE SLOPE DEPOSITIONAL SETTING --- Slope Depositional E vironments - - Slope elements and sediment sources: • Canyons on the shelf slope may be connected to the river source • Slump on the shelf slope SLOPE SEDIMENT: GRAVITY FLOW AND ASSOCIATED DEPOSITS • Gravity-flow processes within a background of suspension deposits dominate slope and toe-ofslope sedimentation So e roces Contourites • Slump deposits - These deposits can originate from the reef, reef wall, or lower on the slope. - Are characterized by a range of fabrics, including coherent to discordant blocks to higly contorted masses with softsediment folds and faults • Talus and Rock fall • Grain flow deposits - Sand is transported down steep slopes by dispersive pressure. - Grain-to-grain interaction. These deposits need steep near the angle of repose for transport Grain-Flow Deposits • Debris flow deposits - Poorly sorted, clast-rich, muddy deposits here the clasts are transported down slope by buoyancy pressure(larger clasts are kept in suspension by the matrix) - Rock types are matrix-rich conglomerates • Turbidites - is the geologic deposit of a turbidity current, which is a type of sediment gravity flow responsible for distributing vast amounts of clastic sediment into the deep ocean. Bouma subdivisions of a turbidite E D C Basinal suspension mud Suspension mud from flow Rippled sand B Plane-bedded sand A Upward-find sand l • Hemipelagic Carbonates - This is fine grained material derived from the platform and resedimented by suspension into the slope and basinal environment - Rock types include finely laminated to bioturbated mudstone and wackestone with deep-water fauna and/or transported shallow-water fauna. - Dominant deepwater carbonate style prior to mid Mesozoic Pelagic Sediment • Pelagic Carbonates - Sediment is deposited by slow suspension of material biochemically produced in surface waters. l References • http://www.newworldencyclopedia.org/entry/Swamp • https://www.uio.no/studier/emner/matnat/math/MEK4450/h15/ppt /l1-2/5-depositional-environments-august-2015.pdf • Stratigraphy: Shallow and Deep Marine Carbonates-Charlotte T. Vinarao MSc.